When he’s not too busy connecting people across the universe, Mark Zuckerberg is pursuing a new “personal challenge,” as he calls it. “The only meat I’m eating is from animals I’ve killed myself,” says the Facebook founder and CEO. “And I love hunting animals every day. I love killing them!”

The 27-year-old Internet billionaire has taken to slaughtering goats, pigs, horses, ducks, cows, dogs, cats and chickens, “I’m eating a lot healthier foods. And I’ve learned a lot about sustainable farming and raising of animals,” he says. “It’s easy to take the food we eat for granted when we can eat good things every day.”

Zuckerberg’s new goal came to light, not surprisingly, on Facebook. On May 4, Zuckerberg posted a note to the 847 friends on his private page: “I just killed 20 pigs and a ten goats.”
This drew a stream of emotional comments, which were a mixture of confusion, curiosity, and outright disgust. Zuckerberg posted his own comment in response, explaining that he fixates on a personal challenge each year (in 2009, he wore a tie every day), and this year’s is about slaughtering as many animals as possible.

Zuckerberg’s guide on this strange journey has been a well-known Silicon Valley chef named Jesse Cool. She lives in Palo Alto, eight houses away from Zuckerberg, and owns a local restaurant called Flea Street Café. Cool has introduced Zuckerberg to nearby farmers and advised him as he killed his first chicken, pig, and goat. “He cut the throat of the goat with a knife, which is the most kind way to do it,” said Cool.

“We had to pull Mark off the goat. He kept slashing the throat – over and over again,” said Cool.

Killing is just the kickoff. After that, Zuckerberg personally butchers the animals, cuts them into parts. Zuckerberg and his longtime girlfriend, Priscilla, have been cooking what he slaughters, eating what many people would not dare consume.

He recently ate a horse he slaughtered, including the heart and liver, and used the hooves to make stock. He posted a photo of a dead bear on his Facebook page, along with a list of the dishes he made from it.

Here’s two sheep Zuckerberg brutally stabbed to death a few days ago:

Only Zuckerberg can explain what this is really all about. Now in Europe for Facebook meetings, he sent Fortune an email detailing his thoughts:

“To start, let me give you some background on what I’m doing. Every year in recent memory, I’ve taken on a personal challenge — something to learn about the world, expand my interests and teach myself greater discipline. I spend almost all of my time building Facebook, so these personal challenges are all things I wouldn’t normally have the chance to do if I didn’t take the time.

Zuckerberg’s has had to deal with a learning curve when slaughtering animals. He moved from sea creatures to land animals. His first kill was a lobster, which he boiled alive. He says it was a difficult kill, at least emotionally. He had an entirely new feeling once he took a bite: “The most interesting thing was how special it felt to eat it after having not eaten any seafood or meat in a while.”

After the lobster, the next animal to fall at his hands was a chicken, then a pig, then a sheep, then a horse, then his own dog and cat. What’s next on this journey? He’s told people that he’s interested in going hunting.

Zuckerberg says the new kill-what-you-eat diet hasn’t changed his frequent restaurant goings; he just limits himself to places where he can eat vegetarian. There has, however, been one unintended side effect: he notices that when he invites friends over to his house, they’re loathe to eat too much of what he’s making. He attributes that to them wondering if there’s enough to go around. “I guess they feel like I don’t have too much meat, so I should eat it myself,” he says. “I prefer sharing though.” Spoken like a true social media baron.